[TheLastSuperman]

This might help you some:
https://vborg.vbsupport.ru/showthread.php?t=256370

See the helpful links near the top.

Basically stylevars are well... Style Variables, we use that system to key in all sorts of info and most of the stylevars are used in the css so instead of regular css for example:

.widget_content {
    color: #515151;
    -moz-border-radius: 5px;
    -webkit-border-radius: 5px;
    background: #ffffff;
    border: #c4c4c4;
    _background-image: none;
    padding: 5px 5px 5px 5px;
}

We will see this:

.widget_content {
    color: {vb:stylevar sidebar_content_color};
    -moz-border-radius:{vb:stylevar border_radius};
    -webkit-border-radius: {vb:stylevar border_radius};
    background:{vb:stylevar sidebar_content_background};
    border:{vb:stylevar sidebar_content_border};
    _background-image: none;
    padding:{vb:stylevar vbcms_widget_content_padding};
}

Now I did not reference the stylevars correctly just used as an example however if you see a CSS definition such as:

    background:{vb:stylevar sidebar_content_background};

Now simply look for... you got it ... the stylevar sidebar_content_background and change it to see the results . It's still being worked on per say (or should be imo) as recently I noticed some sidebar stylevars are used for the widgets as you can note by my css examples lol however they are apparently different systems etc so it's not perfect and not every bit of CSS uses or has a stylevar.